This invention relates to reciprocating piston machines, especially engines, and particularly to internal combustion engines of the reciprocating piston type wherein thrust loads are applied to the piston skirt during operation.
It is known in the art that a portion of the friction loss occurring in reciprocating piston type internal combustion engines is attributable to the friction resulting from the sliding of the piston skirts along the cylinder walls while subject to thrust forces imposed by the working gas and inertia forces applied to the pistons and acting upon the mechanical output crank linkage. Thus, it is recognized that any reduction of the thrust forces between the piston and cylinder should result in a reduction of engine friction losses and increased efficiency.